Just an additional comment to my previous e-mail: the refined final value of occupancies in the expression occupancy(AGLU A 30) = occupancy(BGLU A 30) = occupancy(AALA A 451) = occupancy(BALA A 451) were not equal to 0.50 and I got occupancy(AGLU A 30) + occupancy(BGLU A 30) = occupancy(AALA A 451) + occupancy(BALA A 451) < 1.00. Regards, Dalibor -- Dalibor Milic Laboratory of General and Inorganic Chemistry Department of Chemistry Faculty of Science University of Zagreb Horvatovac 102a HR-10000 Zagreb Croatia phone: +385 1 460 6377 fax: +385 1 460 6341 e-mail: [email protected]